KR20010096420A - Method for Producing a Thermoplastic Coating and Articles Constructed Therefrom - Google Patents

Abstract

The present invention relates to a non-contact coating method and a product thereof for substantially continuous coating. The invention furthermore relates to a non-contact slot coating method and lamination for various coatings. The present invention particularly relates to a method of coating a substrate comprising a film, foil, and paper with a molten thermoplastic composition that reduces streaks caused by particles. The invention also relates to thermoplastic compositions useful in the present non-contact coating method.

Description

Method for Producing a Thermoplastic Coating and Articles Constructed Therefrom}

Conventional slot nozzle coatings that coat a molten thermoplastic composition onto a substrate have typically been done by bringing the slot nozzle into continuous contact with the substrate such that the slot nozzle is placed on the substrate during coating. If the coating does not need to be completely sealed, i.e. nonporous, then there is no problem in coating the hot melt adhesive with a low coating weight. In the context of this specification, "continuous" is used to describe a completely closed, ie nonporous film or coating. However, if a completely closed, ie non-porous coating is made and the coating weight of the hot melt is substantially higher, this coating can only be done using conventional coating methods.

The higher the coating weight, the more expensive it is. In addition, direct coating with slot nozzles imparts substantial mechanical or thermal stress to the coated substrate, especially since the slot nozzles are heated during coating. Therefore, highly sensitive substrates, such as plastic films, are not always able to coat hot melts from slot nozzles in conventional manner without damaging the substrate. In addition, the high coating weight of this prior art makes the coated substrate more stiff.

International Publication No. 96/25902, published August 29, 1996, and assigned to H. B. Fuller, St. Paul, Minn., Discloses that a thermoplastic composition is thermally flowable and without contact between the coating apparatus and the substrate to be coated. Disclosed is a coating method which allows release from the coating apparatus as a continuous coating.

The present invention specifically addresses the use of this new coating method in a variety of other applications involving the coating of nonporous and porous materials. One type of such application is coating a nonporous material such as a film. Thermoplastic compositions often contain particles which do not dissolve in the form of impurities such as contaminants and charcoal, or optionally in the form of dust components such as fillers or additives. If these particles are of detectable size or the slot nozzles have a relatively small gap, they tend to interfere with the deposition of the coating and accumulate in the coating apparatus. These particles prevent the passage of the thermoplastic material, which leads to the formation of flaws or streaks corresponding to the substrate to be coated. This problem is particularly prevalent in the formation of very thin coatings, for example high quality graphics technology applications, especially where optical properties are important where the film should be coated. Therefore, the industry often finds an advantage of a coating method that solves these problems.

It is therefore an important object of the present invention to provide a new coating method suitable for coating films, foils, paper and other such materials, which makes it possible to avoid streaking and nicking problems, especially at very low coating weights.

Another important object of the present invention is to "inline" or "offline" using thin films, metallized foils, heat sensitive materials and other sensitive substrates to reduce the risk of obtaining defective or cracked products. It is to provide a coating method that allows lamination and coating to be carried out).

Yet another important object of the present invention is to make film-to-film and film-to-foil laminations available that do not require the use of reactive adhesives.

Another object of the present invention is to provide an improved coating method for coating a thermoplastic composition, in particular a hot melt adhesive, on a porous substrate such as a fabric.

These and other objects and advantages of the present invention will become more apparent in the following discussion.

The present invention relates to a non-contact coating method and a product thereof for substantially continuous coating. The present invention also relates to a non-contact slot coating method for various coatings and laminations. The present invention relates in particular to a method for coating a substrate comprising a film, foil, and paper with a molten thermoplastic composition that reduces streaks caused by particles, wherein the film-to-film, film-to-foil, and film-to-seal with non-reactive hot melt adhesives It facilitates paper or board lamination.

The present invention relates to a method of coating a substrate with a thermoplastic composition using a non-contact coating method and a product thereof. This method produces a substantial continuous coating, which is useful for a variety of adhesives and coating applications, and in particular for use of conventional slot coating techniques and heat sensitive substrates, which require a low coating weight and produce thermoplastic compositions that make up the particles. Applied to use.

In one aspect, the present invention discloses that a thermoplastic composition, such as a hot melt adhesive, that is thermally fluidized is released onto a nonporous substrate in a coating apparatus as a substantially continuous coating without contact between the coating apparatus and the substrate. It is a coating method that is sequentially processed on the surface.

In another aspect, the present invention provides that a thermoplastic composition, such as a hot melt adhesive, which is thermally fluidized, is released onto a substrate in a coating apparatus as a substantially continuous coating without contact between the coating apparatus and the substrate and onto the substrate surface. It is a coating method which is processed sequentially and the distance between the coating apparatus and the substrate is much more than 20 mm.

In another aspect, the present invention is directed to a substantially continuous non-porous film in which any thermoplastic composition, such as a hot melt adhesive, is made thermally fluidic, without contact of the substrate-to-film, wherein the film is then directly in contact with the adhesive film. Contacting release coated rollers, the rollers by means of either nipping the adhesive with the substrate, or by a release coated second substrate treated on the surface of the thermoplastic composition that is not in contact with the first substrate, or by a transfer coating method. A thermoplastic composition coated on the substrate by means of which it is thermally flowable, such as a hot melt adhesive, is released from the coating apparatus on a roller that is released as a substantially continuous coating, i.e. a non-porous film, without contact between the coating apparatus and the roller. It is a coating method that is sequentially processed on the substrate surface.

In another aspect, the invention provides that a thermoplastic composition, such as a hot melt adhesive, is released onto a first substrate from a substantially continuous coating apparatus that is free from contact between the coating apparatus and the substrate, and subsequently processed onto a surface. And the coating is sequentially reheated and then contacted with the second substrate.

The present invention also relates to the use of lamination methods for laminating materials, in particular transparent film materials, as well as film-to-film and film-to-foil lamination, as well as substrates such as printing paper or cardboard, which methods are described above. The disadvantages of this and the use of such non-reactive hot melt adhesives for film-to-film and film-to-foil lamination are made possible.

For heat sensitive substrates, the thermoplastic composition should be coated at a temperature of about 160 ° C. or less to reduce thermally induced stress on the substrate to be coated, and even more preferably, a temperature of about 125 ° C. or less, most preferably about 110 ° C. or less. to be. Optionally, the distance between the coating apparatus and the substrate to be coated can be increased so that the distance between the coating apparatus and the substrate to be coated can be sufficiently cooled before the molten thermoplastic composition contacts the heat sensitive substrate. This is particularly advantageous for coating heat sensitive substrates and adhering to each other.

The thermoplastic composition is capable of any fluid so that at high shear rates (1,000 radians / second) the complex viscosity is less than about 500 poises and low shear rates (1 radians / second) are less than 1,000 poises at the coating temperature. Should be characterized. Some clean thermoplastics are suitable for the method of the present invention if the viscosity of the unsynthesized material is low enough. However, synthesized hot melt adhesives are preferred because of their ability to independently control viscosity, elastic properties, open time, and the like. The synthesized hot melt also has the advantage of ensuring adequate agglomeration to the carrier substrate, or delayed detackification of the coating after adhesion to the substrate.

The final coating produced by this method is useful for a variety of applications, which is expected to provide a constant, nonporous, substantially continuous coating. A coating weight of less than about 50-60 g / m 2 is preferred but a coating weight of less than about 30 g / m 2 of the thermoplastic composition intended to reduce consumption is more preferred and the feel of the coated substrate is improved. Coating weights of 10 g / m 2 or less can be achieved in many cases.

The final coating may be preferred to make laminations on paper or cardboard, especially on print media. This coating method is particularly advantageous for manufacturing using fewer production steps than prior art coating methods. As well as reducing the coating weight per area and improving the productivity, the coating and corresponding particles are less expensive than the prior art.

However, the coating method is not limited to applications related to nonporous substrates. This creative coating can also be used for porous substrates. Various aspects of the invention can be used here, in which the thermoplastic composition is released from the coating apparatus with a gap between the coating apparatus and the substrate, which is much larger than 20 mm, and the hot melt adhesive film already formed in direct contact with the adhesive film. And a release coated roller by means of biting the porous substrate.

As described herein, the particles are characterized in that the at least one first layer and the second layer are coating or adhesive layers produced from the coating method described above, wherein the first layer is a nonporous substrate. Is a particle having at least one second layer.

1-10 depict some of the preferred embodiments of the present invention, wherein a substantially continuous thermoplastic coating is formed and adhered to the plate.

More specifically, FIG. 1A shows the basic structure of a coating laminating machine useful for operating the present invention.

1B and 1C show the basic structure of such a similar machine.

2-4 show this creative lamination at various locations of the coating apparatus.

5A and B illustrate lamination and transfer coating methods in accordance with the present invention.

Figures 6-10 illustrate laminations including adhesive restart lamination in accordance with the present invention.

In the process of the present invention, a molten thermoplastic composition, such as a hot melt adhesive, is initially given in the form of a substantially continuous nonporous film, which is later brought into contact with the substrate, transfer roller or some other kind of support. Generally, the composition is released in such a way that it exits from the device as a substantially continuous film from the coating or release device. A typical coating apparatus is a slot nozzle, which has been used previously for coatings in direct contact with a substrate. Therefore, the known hot melt coating apparatus can be used according to the method of the present invention in that the slot nozzle is lifted off the substrate and adjusted to have a suitable distance from the substrate.

Since the flowable melt adhesive or thermoplastic composition comes out of the coating apparatus, it does not contact the substrate but rather moves a constant distance as a continuous film that is stationary between the coating apparatus and the substrate. The coating apparatus may initially contact the substrate to fix or adhere the thermoplastic composition to the substrate if the substrate is not thermally or mechanically damaged by contact with the coating apparatus. Optionally, the thermoplastic composition is present as a substantially continuous film through the nozzle and lowered until it contacts the substrate. The main end of the running substantially continuous film of the thermoplastic composition is attached or secured to the substrate in contact with the substrate. In the case of heat sensitive materials, it is advantageous to advance the substrate by means of a drive roll before contacting the thermoplastic mixture to the substrate to avoid accumulation of molten material that will melt as it passes through the substrate.

Suitable machinery for managing this creative method is shown schematically in FIGS. 1A, B and C. FIG. Figures 1A and B show a specific example where the thermoplastic composition is released onto the first substrate 1 in the coating apparatus 3 and the second substrate 4 is then coated with an nip roll 5 The Example processed to the empty surface of was shown. It should be understood that in other embodiments this process may be modified in other forms, and in particular in all cases it is not necessary to use the second substrate 4. The nip roll 5 can then be used to direct the thermoplastic composition to the first substrate. For the embodiment the nip roll 5 may be a steel roller which is release coated, for example a polytetraflow reethylene surface layer.

Substrate 1 (1), shown in more detail in Fig. 1A 1B, passes through a series of idle rollers in order to allow the web to be properly treated before accessing the coating apparatus. Substrate 2 (4) may be selectively adhered to the coating surface by means of the nip roll (5). Substrate 1 can be defined as a first substrate that is in contact with a substantially continuous thermoplastic film. Substrate 1 may be any substrate generally given in rolled products such as nonwovens, various films including release coated papers, foils, and other materials. The embodiment of FIG. 1A is particularly suitable for coating porous substrates, in which the nip roll 5 is located far away from the contact point of the adhesive film with the first substrate. The embodiment of FIG. 1B may be particularly suitable when substrate 1 is nonporous, ie, air does not readily pass through the substrate. In the case of film lamination, Substrate 1 is a conventional film. Substrate 2 may also be provided in a roll product and may be of the same or different material as substrate 1. However, Substrate 2 can also be a dusty material such as a superabsorbent polymer or a release coated web material capable of stripping off the adhesive coating.

FIG. 1C shows an embodiment in which the adhesive film is initially snapped onto the first substrate by a nip roll that is part of the nipping station as shown in rolls A and B of FIGS. 2-10.

The second substrate 4 is treated on an empty surface without contacting the first substrate in the lamination station formed by the rolls C and D.

2-10 illustrate various preferred embodiments of the invention wherein an extruded thermoplastic composition, such as a hot melt adhesive, is attached to a first substrate and then laminated to a second substrate. In each figure, plate 2 is in the broadest sense optional in that the present invention is simply one continuous nonporous film formed from a non-contact coating method and coated on one substrate. If there is no second substrate, Figure 5B shows a transfer coating application since the molten composition is initially attached to a release coated roller in contact with the first substrate on the nip side.

6 and 7, in the absence of a second substrate, or when the second substrate is porous, the thermoplastic composition or hot melt adhesive is contacted with the first substrate in an embodiment. It is important to have a release coating, such as silicone, teflon, or release paper, on the roller that contacts the adhesive or porous substrate to prevent sticking. The nip roller compresses and extracts air from the thermoplastic coating film and the substrate so that there are no air holes (traps) between the first substrate and the thermoplastic composition. Roller A is a steel cylinder to promote heat transfer while roller B, or the nip roller, is usually rubber. In some cases roller A is a rubber while roller B is a steel cylinder with an outer release coating.

3-10 show the positions of the nozzles varied from vertical to horizontal in the position of the substrate.

8 and 9 show a second substrate laminated to the first substrate at a location remote from the coating apparatus. In this embodiment, roller C is preferably heated to reactivate or extend the open time of the hot melt adhesive or thermoplastic coating prior to lamination to the second substrate. The temperature of roller C varies between about 30-100 ° C. for lamination between rollers C and D. Optionally, roller C may be a chill roll to speed up the set of thermoplastic coatings or hot melt adhesives. This is useful for producing intermediate storage laminations. The laminated substrate in the nip of the roller is in the form of a web or sheet. Where Roller C is a chill roll, as shown in FIG. 10, this inventive method can be used to produce substrates, such as films coated only on one side with a thermoplastic composition, for example in heat seal applications. In order to protect the heat-sealing material for example intermediate storage where this method is expected, one more layer of release paper is of course attached, as shown in FIG. 9.

The coating apparatus is positioned at a distance of at least 0.5 mm, possibly 2 mm, from the substrate (or release coated roller in the case of transfer coating because there is no second substrate-FIG. 9). The maximum distance of the position where the coating device is to be placed on the substrate is limited only because of practicality, especially when the coating device is positioned substantially vertically. If possible, the distance is preferably less than about 5m, more preferably less than about 3m, more preferably less than about 1m, even more preferably less than 500mm and most preferably about 2mm to 20mm, which is a coating It depends on the properties of the thermoplastic composition. It is a common advantage to protect the area (space) between the coating apparatus and the substrate from airborne contaminants and airflow to prevent distortion of the coating prior to contacting the substrate during coating. This is especially the case when the distance between the coating apparatus and the substrate is much larger than about 500 mm.

The distance is largely dependent on the viscosity and open time of the coated thermoplastic composition. When producing a barrier film in this manner, it is believed that the thermoplastic composition cools sufficiently in a stationary state to incorporate viscous and cohesive forces such that the filaments or fibers on the plate surface do not pass through the coating. However, the thermoplastic composition is still sufficiently melted to properly adhere to the substrate. The greater the distance between the coating apparatus and the nip roller, the faster the hot melt adhesive or coating will cool down before contacting the first substrate. For some adhesive compositions such cooling will rather affect the substrate and cohesion (or fixation). Therefore, a heated nip roller can be used if the substrate passes over the heated roller before biting or if the coating cools down so that it is no longer properly attached or fixed to the substrate due to the distance between the nip roller and the coating apparatus.

The coating can be contacted with the substrate at any angle (compare FIGS. 3 and 4). However, for some applications, such as barrier films, this coating has been shown to be particularly advantageous for later contact with the substrate in a substantially horizontal direction as in FIGS. 1A, 1B, 2, 6 and 8. To accomplish this, rollers are applied to the path of movement of the substrate in a substantially vertical, ie upward direction, as the substrate passes through the coating apparatus. In addition, a coating device such as a slot nozzle is applied substantially perpendicular to the roller to allow the coating to move on the side facing the surface of the substrate.

The diameter of the coating roll is preferably about 15 mm to 50 mm with the nozzle slightly above the center of the coating roll so that the angle at which the thermoplastic coating contacts the substrate is not about 60 ° C. when the substrate is moving from the nozzle. The coating head is adjusted by one general technique in the art for optimizing even the flow and distribution of the thermoplastic coating over the full range of applications.

The sufficiently cooled coating then contacts the substrate surface and adheres to the surface without penetrating deeply into the substrate. If the thermoplastic coating is a composition that is substantially sufficiently cooled and then peeled off, the lamination of the formed coated substrate can thus be rolled up and stored. Alternatively, this can be achieved by placing a release coated second substrate, such as a paper coated with silicone, on the surface of the adhesive coating. Then the laminator is used later. The laminate is bonded by any suitable bonding technique, including ultrasonic bonding, heat sealing, or more commonly adhesive bonding.

If possible, it should be done "inline" just before the coating proceeds further. An example of inline treatment in which the invention is particularly well suited can be found in the reference of DE 195 46 272 by Billhofer Maschinenfabrik GmbH. The surface of the coating layer, which is distinct from the substrate, is sufficiently sticky so that it can be used as a lamination for construction adhesives or other substrates, and thus also serves to bond the coated substrate with the other substrate layer. Other substrates bonded or laminated simultaneously in this manner include adsorbents, superabsorbent polymers, elastic bands or webs, tissues, films, foils, paper, cardboard, and metals, as well as various permeable cover materials such as nonwovens and perforated films. . Such materials may be in the form of roll products, sheets (thin substrates), or particles.

In a preferred embodiment, the substrate to be laminated is used for the production of, for example, book covers, postcards, calendars, posters, high quality batch materials, wrapping papers, etc., so that paper cardboard, in particular printing paper, processed photographic paper, printing It is cardboard. The laminating material is a synthetic film material, paper, textile material or any other flexible laminating material suitable for lamination. However, if possible the laminating material is a synthetic film material, in particular a clean and transparent film material used for such lamination in the prior art.

Typically such film materials constitute flat or raised films, which are at least substantially trademarked Mylar, having a thickness of about 5 microns to about 50 microns. It is made of oriented polypropylene, polyethylene, polyester such as polyacetate, nylon, cellulose acetate. Such films are usually laminated or sealed on print or board paper. Mixtures are often produced, including film-to-film and film-to-foils, and metallized substrates are often used in laminates. Laminates of this type are commonly found in industries such as graphics technology or batch processing. Such laminates are produced using an unreacted hot melt adhesive instead of the commonly used reactive adhesives using the method of the present invention.

Generally, the outlet temperature of the thermoplastic composition will be less than about 240 ° C. Thus, it is much lower than the usual polymerization injection temperature of 300 ° C. When the composition comes out of the coating apparatus, the coating is done at extremely low temperatures with the non-contact coating system of the present invention, although the temperature range of the thermoplastic composition ranges from about 80 ° C to about 180 ° C. Regarding this embodiment, it is preferred that the thermoplastic composition be coated at a temperature below 160 ° C, more preferably below 140 ° C, more preferably below 120 ° C, most preferably below 110 ° C. As mentioned previously, heat sensitive materials can also be coated in this way by using higher coating temperatures in conjunction with increasing the distance between the coating apparatus and the substrate to be coated to allow for sufficient cooling. Therefore, materials that are normally too sensitive to machine or temperature (eg very low dimension films) for conventional coating methods can be coated using the method of the present invention. Such sensitive materials include low dimension polyethylene materials, low basis weight nonwovens, and the like.

A substantial advantage of the present invention is that it is possible to make a substantially continuous coating layer with hot melt at very low coating weight. Even with conventional commercially available hot melts, it is possible to produce continuous layers with coating weights ranging from about 0.5 g / m 2 to about 50-60 g / m 2, preferably at least about 30 g / m 2. More preferably no more than about 20 g / m 2, even more preferably no more than about 10-20 g / m 2, most preferably no more than 10 g / m 2. However, coating weights higher than 60 g / m 2 are useful for other applications where mechanical and thermally induced stress reduction are the most important features.

The very thin coatings produced according to the invention not only contribute to the economic advantages of this creative method, but also make it possible to reduce the stiffness of the material, which is close in nature to the uncoated substrate.

As mentioned previously, various thermoplastics can be used in the present invention, such as polyethylene, polypropylene, olefin interpolymers, in particular ethylene, and (methyl group) acrylic acid derivatives, especially (methyl group) acrylic acid esters; Olefin interpolymers, in particular ethylene, and vinyl carboxylates such as vinyl group compounds, especially vinyl acetate; Thermoplastic rubber (or synthetic rubber) such as styrene-isoprene-styrene, styrene-butadiene-styrene, styrene-ethylene / butylene-styrene and styrene-ethylene / propylene-ethylene block kraton , Solprene , And Stereon Interpolymers commercially available under the registered trademark; In particular ethylene or propylene new metal-catalyzed interpolymers; Polyolefins, polypropylene and trademarks Vestoplast, such as ethylene Aromatic polyolefins (hybridized poly-alpha-olefins) such as 703 (huls); Polyester; Ionomers) and the corresponding interpolymers; And mixtures thereof. Such thermoplastics can be used without formulation in the coating process of the present invention if the thermoplastics are sufficiently low in viscosity. However, hot melt adhesives are preferred because of their ability to independently create viscoelastic properties, open type, adhesion, and many other features. Hot melt adhesives generally have the melt flow index needed for such a process already at very low temperatures. Conventional hot melts are sufficiently fluid for such processing at temperatures ranging from about 60 ° C to about 175 ° C. In addition, well known pyrolytic moisture cure compositions are expected in the use of the present invention.

Suitable hot melts, such as those described in DE-A-41 21 716, for example, can produce materials that are impermeable to liquid water, but water vapor can be permeated by making the coating "breathable". Can be.

The main end of the substantially moving continuous film of the thermoplastic composition is attached or secured to the substrate in contact with the substrate. In addition to the commonly known hot melt adhesives, thermoplastic compositions comprising salty (in vivo) insoluble polymers such as soluble, commercially available Eastman AQ interpolyesters are also particularly useful for making body film invasive fluids. But it is easily soluble in water. Its features are particularly beneficial for making hygienic products that are red-mixable and freely disposable. In addition, it may be an application characterized by the desire for permeability. Thus, this coating method is also suitable for coating soluble or microbially separable thermoplastics.

Thermoplastic polymers which comprise or comprise one or more of ethylene / methylacrylate interpolymers (EMA's) / ethylene / n-butyl acrylate interpolymers (EMA's) in the case of transparent substrate lamination adhesives are preferred. EnBA interpolymers are such polymers that are currently most preferred.

Further, if possible, the thermoplastic mixture must exhibit some fluid character such that a substantial continuous coating can be produced at a weight of about 50-60 g / m 2 or less, preferably about 30 g / m 2 or less. In general, the fluid properties can be less than about 500 poises at high shear rates (1,000 radians / sec) coating temperature and less than about 1,000 poises at low shear rates (less than 1 radian / second). It is desirable to fall into a fluid window characterized by: In other words, preferred thermoplastic compositions exhibit low shear rate Newtonian regions and are thinly sheared at higher high shear rates. Thermoplastic compositions with wide application windows are those in which the composition exhibits suitable fluid characteristics at various application backgrounds, particularly at low application temperatures. Narrow application windows appear only when fluid parameters are fitted under very clear conditions.

Applicants believe that complex viscosity and high shear are related to the processing conditions of the slot formwork exit. For compositions with too high complex viscosity at 1,000 radians / second, excessive pump pressure needs to be present in the coating apparatus. Formwork with wedge gaps well over 3 mm may be used to treat these materials but may result in higher coating weights.

Complex viscosity and low shear relate to coating a substrate while stationary on the substrate. The low shear value may be so high that the coating may not adhere properly to the substrate or the thermoplastic composition may build up on the nozzles resulting in streaks or breaks in the coating. The low shear viscosity can be so low that the coating can seep into the substrate causing poor barrier properties.

Unexplained elongated viscosity can also have a strong effect on solubility. Higher branching levels or the addition of small concentrations of high molecular weight materials can have a strong effect on solubility. At lower application temperatures of about 177 ° C. or less, preferably 160 ° C. or less, more preferably 125 ° C. and most preferably 110 ° C. or less, a composition suitable for the subject flow parameters is more preferred.

Therefore, the well-known hot melt adhesive composition is very suitable for using the coating method of the present invention. Hot melt adhesives typically comprise at least one thermoplastic polymer, one plasticizer and one tackifier. If possible, such suitable hot melt should comprise up to 50% of the weight of the thermoplastic polymer, 40% of the weight of the plasticizer, and up to 70% of the weight of the tackifier. In the case of hot melt adhesives that are not pressure sensitive, waxes are generally used at concentrations up to about 30% of the weight of the adhesive.

In general, the hot melt of the present invention may further contain one or more adhesive strengthening resins, plasticizers, or oils and waxes, as well as conventional additives and auxiliaries such as safety devices, antioxidants, pigments, UV safety devices or absorbers, supplements, and the like. Will contain. Plasticizers and tackifier resins used as high temperature melting adhesives are known.

Oils such as naphthenin oil are preferred as plasticizers. With regard to tackifiers, resins already known for that purpose are generally suitable, in particular aliphatic cycloaliphatic or aromatic hydrocarbon resin ester resins and other such compatible resins. At present, preference is given to using aliphatic or aromatic modified carbon hydroxide resins. Preferred aliphatic resins are hydrogenated aliphatic hydrocarbon resins. For example, Escorez from Exxon Chemical Company in Houston 5000 Series, TX & the Arkon from Aragawa Chemical Company Regalite from P & M series and Hercules subsidiary in Wilmington, Germany Series. Rosin and rosin ester resins are also useful in the present invention. One such hydrogen-generating rosin acid tackifier was Foral from Hercules. AX. Zonatac from Arizona Chemical Company in Panama City, Florida Kristalex from Alpha-Methyl Styrene from Hercules Series, and Uratack from Arizona Chemistry Modified hydrocarbon resins such as modified terpins, including styrenated terpins such as series, are also useful in the present invention. These components are mixed in a known manner to prepare the hot melts to be used according to the invention.

Waxes are also useful in the present invention. This is Paraflint Marcus from Fischer Tropsch Wax, from Sasol (South Africa) or Shell Malaysia under the Petrolite trademark Contains high melting point synthetic waxes such as high density, low molecular weight polyethylene wax from Marukus Chemicals. AC 8 is another useful polyethylene wax from elite chemistry. Microcrystal waxes and paraffin waxes are also useful in the present invention.

Laminating adhesives include at least one of the 100% thermoplastic polymers mentioned above; Aliphatic hydrocarbon resin 0-50%; Aromatic hydrocarbon resin 0-20%; 0-40% rosin and 0-20% wax and the selected amount of ingredients and ingredients such that the adhesive can be coated inline to the laminating material or laminating substrate for sequential inline lamination to the substrate. Would be desirable.

More preferably in the case of film laminating it will be preferred that the adhesive constitutes the following components. The component is at least one 100% interpolymer of EMA or EnBA, 0-50% hydrogenated aliphatic hydrocarbon resin, 0-20% alpha-methyl styrene resin, 0-40% hydrogen rosin and 0-20% polyethylene wax .

In the simplest case, the hot melt adhesive that can be used to practice the method of the present invention constitutes one or more grades of EMA or EnBA interpolymers substantially or even completely. EMA and EnBA interpolymers are Lotryl In Elf Atochem, Quantum Chemical Recall, Optema Is registered trademark of Exxon Chemical Company. Many different grades of EMA and EnBA interpolymers are also available. They differ mainly in ester content, melt flow index (MFI), and melting point.

In a presently preferred embodiment, the hot melt adhesive is essentially 35-60% EMA or EnBA; 30-50% hydrogenated aliphatic hydrocarbon resin or about 10% alpha-methyl styrene resin; 0-30% hydrogen rosin, 0-10% polyethylene wax, and a small amount of stabilizer. In some preferred embodiments, the thermoplastic polymer of the hot melt adhesive is usually only one grade of EnBA interpolymer at the low end of the MFI range (ie, less than 10 g / 10 min of MFI). In another preferred embodiment, the thermoplastic polymer comprises at least one grade of EnBA, in which case at least two of the grades have a factor difference of at least 4 to 10 factors (ie, one grade differs from the MFI). And quadruple differences), including two or three different grades characterized by a range of MFIs.

This creative hot melt can be used at sufficiently low application temperatures (process temperatures) to prevent distortion of heat sensitive plastic films, while at the same time exhibiting good flow characteristics at such low temperatures. For example, the creative hot melt can be coated and laminated to a laminating material. Non-contact coatings are particularly advantageous for heat sensitive films. Excellent film forming performance is achieved and the laminated product exhibits high gloss.

Since the laminating adhesive of the present invention increases the transparency of the hot melt coating, it achieves high gloss and at the same time does not impair readability and color rendering on the substrate.

This creative hot melt exhibits not only setting characteristics but also good (high) high temperature adhesion and open time properties for the present invention. They meet the requirements of machine conditions, for example, inline cutting and cutting in the graphics technology industry.

Laminates made according to the invention exhibit high heat resistance and high UV resistance, with correspondingly no thinning or yellowing. Also, after heating and ramping, no cracking can be observed when using the hot melting formula of the present invention.

The following non-limiting examples also serve to illustrate the present invention.

As shown in Table 1 below, hot melt adhesives were produced from various thermoplastic polymers, pressure sensitive adhesives, and plasticizers.

Example 1-8

TABLE 1

ingredient Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Lotryl 17 Ba 07 EnBA Copolymer 23 40 35 10 23 - - - Lotryl 35 BA 40 EnBA Copolymer 15 - - 20 15 20 15 15 Lotryl 35 BA 320 EnBA Copolymer 17 - - 30 17 10 15 Escorene UL 150-19EVA Copolymer - - - - - 20 24 23 AC-8 Polyethylene Wax 5 10 - - 5 5 - - Paraflint C 80 polyethylene wax - - - - - 10 - - Mobil wax 145 Paraffin Wax - - - - - - - 5 Escorez 5300 hydrocarbon resin 28 38 38 38 - 23 28 30 Foral AX Rosin Acid Resin 10 10 25 - 28 15 10 10 Kristalex F 85 alpha-methyl-styrene resin - - - - 10 - - -

The mixture described in Examples 1 and 7 and the corresponding hot melt adhesive were coated onto the substrate using a modified PAK laminating machine made by Kroenert in Hamburg, Germany. The structure of this machine is basically similar to that shown in Figure 1B. With this type of machine, the adhesive film is directly engaged with the first substrate 1 by means of the nip roller 5 or the second substrate 4 is engaged with the adhesive with the first substrate by means of the nip roller 5 again. can do. In the test, both methods were tested. The running temperature of this hot melt was 140 ° C. for the mixture of Example 1 and 110 ° C. for the mixture of Example 7. This mixture shows a favorable low viscosity as is evident in the diagram of FIG. This diagram illustrates the viscosity of Examples 1 and 7.

Coatings were made on polyester films (forester RN36 manufactured by Putz Folien in Taunusstein-Wehen, Germany) and high-density polyethylene films (HDPE KC 3664.00 from Mildenerger + Willing, Gronau, Germany).

As the second substrate (where used), these films were also used. In other experiments, silicon paper was used instead. Moreover, it tested by the paper sheet for printing as a 2nd base material.

The coating weight was 5 to 6 g / m 2 at a machine speed of approximately 70 m / min.

The adhesive film was released from the coating slot nozzle at various distances from the first substrate to be coated with the adhesive in various tests. In another experimental set (similar to FIGS. 3-5, 7, 9, and 10), the vertical treatment allows the slot nozzle distance from the substrate to a few millimeters to 500 mm without materially affecting the properties of the coating. Found that it can change. In this experiment it was found that the adhesive film released in the coating slot nozzle did not stick to the nip roller where it was coated on the first substrate directly by means of the nip roller 5 imparted to the release coating. No nip pressure was measured but the nip roller was pressurized facing the substrate at a laminating pressure of 7 to 8 atmospheres.

The adhesive coated on the first substrate was found to exit the nip position without the air tightly sealed between the adhesive and the first substrate.

In another experiment the second substrate was coated on the adhesive layer by a second set of rollers located in the flow path of the substrate upstream of the nip roller 5. In addition, as discussed above, these laminations using the same film or release coated paper were inspected for streaks, airtight air, or other lamination defects.

The laminations thus made were not cracked. Streaks, airtight air, or any other defects were not observed.

In a similar manner, laminations were made using the same type of film and other adhesives described in Examples 2 through 6 in Table 1. The results are as good as the results obtained with the adhesive compositions of Examples 1 and 7.

The present invention relates to a thermoplastic coating method, which facilitates film-to-film, film-to-foil, and film-to-paper or board lamination with an unreacted hot melt adhesive.

Claims (28)

A thermally flowable hot melt adhesive is released from a coating apparatus into a substantially nonporous substrate as a substantially continuous coating without contact between the coating apparatus and the substrate and subsequently processed onto the surface of the substrate. A thermally fluidized hot melt adhesive is released from the coating apparatus to a substantially nonporous substrate as a substantially continuous coating without contact between the coating apparatus and the substrate and subsequently processed onto the surface of the substrate, between the coating apparatus and the device material. The coating method, characterized in that the distance of 20mm or more. The thermally soluble hot melt adhesive is imparted in the form of a substantially continuous non-porous film without the film contacting the substrate or rollers, which film is coated onto the substrate by a release coated roller in direct contact with the adhesive film. The roller is a coating method, characterized in that for nipping the adhesive and the substrate. A thermally flowable hot melt adhesive is released onto a roller coated with a release coating from the coating apparatus as a substantially continuous coating without contact between the coating apparatus and the rollers and subsequently processed onto the surface of the substrate. The thermally soluble hot melt adhesive is imparted in the form of a substantially continuous nonporous film without the film contacting the substrate, the film being coated on the first substrate, and the release coated substrate not contacting the first substrate. A coating method, characterized in that the treatment on the surface of the hot melt adhesive. The thermally flowable hot melt adhesive is imparted in the form of a substantially continuous nonporous film without contacting the film with the substrate, which film is treated on a release coated substrate and then transfer coated onto a second substrate. Coating method .. A thermally soluble hot melt adhesive is released to the first substrate in the coating apparatus as a substantially continuous coating and sequentially treated on the surface of the first substrate without contact between the coating apparatus and the first substrate, the coating being reheated. And then contact with the second substrate. A thermally flowable thermoplastic material is imparted in the form of a substantially continuous nonporous film without contacting the film with the substrate and coated on the substantially nonporous substrate. And wherein the thermally flowable thermoplastic is released from the coating apparatus at a temperature of about 240 ° C. or less in the form of a substantially continuous nonporous film without contacting the film and the substrate, and then the film is coated onto the substrate. A thermally flowable thermoplastic is imparted in the form of a substantially continuous porous film without contacting the film with the substrate, and then the film is coated onto the substrate, the coating being about 1000 radians / second at a coating temperature of about 500 poise or less. Coating method characterized by having a complex viscosity. Thermoplastic coatings that are thermally fluid and have a complex viscosity of less than about 500 poise at about 1000 radians / second at a coating temperature are released to the nonporous substrate in the coating apparatus as a substantially continuous coating without contact between the coating apparatus and the substrate, Coating method characterized in that it is sequentially processed on the surface of the substrate. Thermoplastic coatings that are thermally fluid and have a complex viscosity of less than about 500 poise at about 1000 radians / second at a coating temperature are released to the substrate in the coating apparatus as a substantially continuous coating without contact between the coating apparatus and the substrate, Processed sequentially on the surface of the coating method, characterized in that the distance between the coating device and the substrate is 20mm or more. Thermoplastic coatings that are thermally flowable and have a complex viscosity of less than about 500 poises at about 1000 radians / second at a coating temperature are substantially continuous coatings without a contact between the coating device and the first substrate and as a first substrate in the coating device. Wherein the coating is re-heated and then contacted with the second substrate. Thermoplastic coatings that are thermally flowable and have a complex viscosity of less than about 500 poise at about 1000 radians / second at a coating temperature are released on the rollers released in the coating apparatus as a substantially continuous coating without contact between the coating apparatus and the rollers. , The coating method characterized in that the treatment on the surface of the substrate sequentially. 15. The method of any of claims 8-14, wherein the thermoplastic coating has a complex viscosity of less than 1000 poise at about 1 radian / second at a coating temperature. The coating method according to any one of claims 1 to 15, wherein the substrate is selected from the group consisting of film, foil, paper, and combinations thereof. 17. The method of claim 16, wherein the first and second substrates are selected from films, foils, paper, coated papers, integrally extruded films, and other laminating materials, wherein the adhesive is a non-reactive adhesive or a reactive hot melt adhesive. Coating method made with. 17. The method of claim 15 or 16, wherein the coated substrate comprises a heat seal material. The coating method according to any one of claims 1 to 18, wherein the coating apparatus is a slot nozzle. 20. The method of any one of claims 1 to 19, wherein the coating has an area weight of about 60 g / m 2 or less. The coating method according to claim 1, wherein the coating has an area weight of about 30 g / m 2 or less. 22. The method of any one of claims 1 to 21, wherein the coating has an area weight of about 10 g / m 2 or less. The coating method according to claim 8, wherein the thermoplastic composition is released from the coating apparatus at a temperature of about 160 ° C. or less. The coating method according to claim 8, wherein the thermoplastic composition is released from the coating apparatus at a temperature of about 110 ° C. or less. 25. The method of any one of claims 1 to 24, wherein the first substrate is bonded to the at least one second substrate "inline" or "offline". The coating method according to any one of claims 1 to 25, wherein the distance between the coating apparatus and the substrate is from about 0.5 mm to 500 mm. A book cover made by the method of any one of claims 1 to 26. A lamination made by the method of any one of claims 1 to 26.